package com.shengruan.common;

import java.io.*;

public class Base64
{
    private static final byte CR = '\r';
    private static final byte LF = '\n';

    static public char[] encode(byte[] data)
    {
        return encode(data, 0, data.length);
    }

    static public char[] encode(byte[] data, int offset, int length)
    {
        byte[] buffer = new byte[length];
        System.arraycopy(data, offset, buffer, 0, length);

        char[] out = new char[ ( (buffer.length + 2) / 3) * 4];
        for (int i = 0, index = 0; i < buffer.length; i += 3, index += 4)
        {
            boolean quad = false;
            boolean trip = false;

            int val = (0xFF & (int) buffer[i]);
            val <<= 8;
            if ( (i + 1) < buffer.length)
            {
                val |= (0xFF & (int) buffer[i + 1]);
                trip = true;
            }
            val <<= 8;
            if ( (i + 2) < buffer.length)
            {
                val |= (0xFF & (int) buffer[i + 2]);
                quad = true;
            }
            out[index + 3] = alphabet[ (quad ? (val & 0x3F) : 64)];
            val >>= 6;
            out[index + 2] = alphabet[ (trip ? (val & 0x3F) : 64)];
            val >>= 6;
            out[index + 1] = alphabet[val & 0x3F];
            val >>= 6;
            out[index + 0] = alphabet[val & 0x3F];
        }
        return out;
    }

    static public byte[] decode(char[] data) throws Exception
    {
        return decode(data, 0, data.length);
    }

    static public byte[] decode(String data) throws Exception
    {
    	if(data==null||"".equals(data))
    		return "".getBytes();
    	else
    		return decode(data.toCharArray());
    }

    static public byte[] decode(char[] data, int offset, int length) throws
        Exception
    {
        char[] buffer = new char[length];
        System.arraycopy(data, offset, buffer, 0, length);

        int tempLen = buffer.length;
        for (int ix = 0; ix < buffer.length; ix++)
        {
            int value = codes[buffer[ix] & 0xFF];
            if ( (value < 0) && (buffer[ix] != 61))
            {
                --tempLen;
            }
        }

        int len = ( (tempLen + 3) / 4) * 3;
        if (tempLen > 0 && buffer[tempLen - 1] == '=')
        {
            --len;
        }
        if (tempLen > 1 && buffer[tempLen - 2] == '=')
        {
            --len;
        }
        byte[] out = new byte[len];

        int shift = 0;
        int accum = 0;
        int index = 0;

        for (int ix = 0; ix < buffer.length; ix++)
        {
            int value = codes[buffer[ix] & 0xFF];
            if (value >= 0)
            {
                accum <<= 6;
                shift += 6;
                accum |= value;
                if (shift >= 8)
                {
                    shift -= 8;
                    out[index++] = (byte) ( (accum >> shift) & 0xff);
                }
            }
        }

        if (index != out.length)
        {
           
        }

        return out;
    }

    static public String removeCRLFAndBlank(String str)
    {
        StringBuffer buffer = new StringBuffer();
        char[] data = str.toCharArray();
        for (int i = 0; i < data.length; i++)
        {
            if (data[i] == ' ' || data[i] == '\r' || data[i] == '\n')
            {
                continue;
            }
            buffer.append(data[i]);
        }
        return buffer.toString();
    }

    static private char[] alphabet =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=".
        toCharArray();
    static private byte[] codes = new byte[256];
    static
    {
        for (int i = 0; i < 256; i++)
        {
            codes[i] = -1;
        }
        for (int i = 'A'; i <= 'Z'; i++)
        {
            codes[i] = (byte) (i - 'A');
        }
        for (int i = 'a'; i <= 'z'; i++)
        {
            codes[i] = (byte) (26 + i - 'a');
        }
        for (int i = '0'; i <= '9'; i++)
        {
            codes[i] = (byte) (52 + i - '0');
        }
        codes['+'] = 62;
        codes['/'] = 63;
    }

    public static byte[] decode(String start, String end, char[] buffer) throws
        Exception
    {
        return Base64.decode(start, end, buffer, 0, buffer.length);
    }

    public static byte[] decode(String start, String end, char[] buffer,
                                int offset, int length) throws Exception
    {
        // ����ȥ���ײ�
        String line = new String(buffer, offset, length);
        if (line.startsWith(start))
        {
            line = line.substring(start.length());
        }

        // ȥ��س��ͻ���
        byte[] tempBuffer = line.getBytes();
        ByteArrayOutputStream bout = new ByteArrayOutputStream();
        DataOutputStream out = new DataOutputStream(bout);
        for (int i = 0; i < tempBuffer.length; i++)
        {
            byte b = tempBuffer[i];
            if (b != (byte) CR && b != (byte) LF)
            {
                try
                {
                    out.writeByte(b);
                }
                catch (IOException ex)
                {}
            }
        }
        tempBuffer = bout.toByteArray();

        // ȥ��β��
        line = new String(tempBuffer);
        if (line.endsWith(end))
        {
            line = line.substring(0, line.length() - end.length());
        }

        // ��BASE64����
        byte[] decoded = null;
        decoded = Base64.decode(line.toCharArray());
        return decoded;
    }

    public static char[] encode(String start, String end, byte[] inBuffer)
    {
        return Base64.encode(start, end, inBuffer, 0, inBuffer.length);
    }

    public static char[] encode(String start, String end, byte[] inBuffer,
                                int offset, int length)
    {
        try
        {
            char[] buffer = Base64.encode(inBuffer, offset, length);
            StringBuffer sb = new StringBuffer();
            sb = sb.append(start);
            sb = sb.append( (char) CR);
            sb = sb.append( (char) LF);
            int count = buffer.length / 64;
            int i = 0;
            for (i = 0; i < count; i++)
            {
                char[] temp = new char[64];
                System.arraycopy(buffer, i * 64, temp, 0, 64);
                sb = sb.append(new String(temp));
                sb = sb.append( (char) CR);
                sb = sb.append( (char) LF);
            }
            int reserved = buffer.length % 64;
            char[] temp = new char[reserved];
            System.arraycopy(buffer, i * 64, temp, 0, reserved);
            sb = sb.append(new String(temp));
            if (reserved != 0)
            {
                sb = sb.append( (char) CR);
                sb = sb.append( (char) LF);
            }

            sb = sb.append(end);
            sb = sb.append( (char) CR);
            sb = sb.append( (char) LF);
            return sb.toString().toCharArray();
        }
        catch (Exception e)
        {
            return null;
        }
    }
}
